Reduced complexity automatic fiber placement apparatus and method

ABSTRACT

A method of forming a composite layup on a substrate comprises: moving an automatic fiber placement head over the substrate; using the fiber placement head to lay down multiple, parallel strips of composite tape on the substrate, including staggering the start of at least certain of the tape strips so as to form a contour pattern; and, cutting the ends of all of the tape strips using a single cut.

This application is a divisional of application Ser. No. 12/038,155filed Feb. 27, 2008, status allowed.

TECHNICAL FIELD

This disclosure generally relates to automated fiber placement systems,especially those used to layup composite structures, and deals moreparticularly with a simplified apparatus for the placing fibers as wellas a related method.

BACKGROUND

Composite structures such as those used in the automotive, marine andaerospace industries may be fabricated using automated compositematerial application machines, commonly referred to as automated fiberplacement (AFP) machines. AFP machines may be used in the aircraftindustry, for example to fabricate structural shapes and skin assembliesby wrapping relatively narrow strips of composite, slit tape or “tows”,collimated into a wider band, around a manufacturing tool. The AFPmachine aligns and places a plurality of tape strips, typically six ormore, in continuous, edge to edge contact forming a single wide,conformal bandwidth which is placed on and compacted against the tool.

In order to fabricate large, complex laminated composite assemblies,current AFP machines may use fiber placement heads having a relativelyhigh degree of operational flexibility. For example, current placementheads may have the ability to add drop-off or cut any or all of thecontiguous tape strips independently of all others by providingseparate, independently controllable cutters for each tape strip.Current placement heads therefore may be relatively complex, large andheavy.

The size, weight and complexity of current placement heads may precludetheir use in fabricating relatively small composite laminate assemblies,or in fabricating layups that require relatively high placementresolution. Moreover, because of their complexity, current placementheads are relatively expensive.

Accordingly, there is a need for automatic fiber placement apparatusthat has reduced mechanical complexity and is both smaller in size andlighter in weight for those fiber applications requiring higherplacement resolution and/or simplified tape application. Further, thereis a need for a method of fiber placement using less complex placementmachines that allows fiber placement forming ramped or contoured tapepatterns.

SUMMARY

Automatic fiber placement apparatus and related methods are providedwhich are particularly useful in fabricating relatively small, laminatedcomposite fiber structures, and as well as larger composite structuresrequiring a high degree tape placement resolution. The complexity, sizeand weight of the placement head is reduced by employing a singlecutting mechanism to simultaneously cut the ends of all of the tapestrips at the end of a course, thus eliminating the need for separatecutting mechanisms for each tape strip. In spite of this reducedmechanical complexity, contoured or ramped tape application patterns maybe achieved by sequentially starting the placement of each tape strip asa band of strips are laid down.

According to one disclosed embodiment, a method is provided for forminga composite layup on a substrate, comprising: moving an automatic fiberplacement head over the substrate; using the fiber placement head to laydown multiple, parallel strips of composite tape on the substrate,including staggering the start of at least certain of the tape strips soas to form a contour pattern; and, cutting the ends of all of the tapestrips using a single cut. Cutting the ends of the tape strips may beperformed by passing a single cutting blade through all the tape stripsubstantially simultaneously.

According to another method embodiment, placing composite fiber tape ona substrate using an automatic fiber placement head comprises: movingthe fiber placement head across the substrate from a starting positionto an ending position; sequentially starting the placement of individualfiber tape strips onto the substrate to form a band as the placementmoves from the starting position to the ending position; and, cuttingall of the tape strips in the band substantially simultaneously at theending position. Sequentially starting the placement of the individualfiber tape strips may be performed by sequentially activating individualtape threading mechanisms on the fiber placement head. Cutting all thetape strips may be performed by activating a single cutting blademechanism on the fiber placement head and using the single cutting blademechanism to cut all the tape strips.

According to a further method embodiment, a composite fiber layup isformed on a substrate having a substrate feature, comprising: moving anautomatic tape placement head across the substrate away from thesubstrate feature in a first direction; using the placement head to laydown a first band of composite tape strips as the placement head movesacross the substrate in the first direction, including staggering thestarting points of at least certain of the tape strips in the firstgroup to form a ramp pattern on one side of the substrate feature;cutting all of the tape strips in the first band at an ending point ofthe tape strips in the first band; moving the automatic tape placementhead across the substrate away from the substrate feature in a seconddirection; using the placement head to lay down a second band ofcomposite tape strips as the placement head moves across the substratein the second direction, including staggering the starting points of atleast certain of the tape strips in the second band to form a secondramp pattern on another side of the substrate feature; and, cutting allof the tape strips in the second band at an ending point of the tapestrips in the second band. Cutting the tape strips in the first andsecond bands is performed by passing a single cutting blade through allthe tape strips in the group substantially simultaneously. Laying downthe tape strips in each of the first and second bands may be performedduring a single pass of the placement head. Movement of the placementhead in each of the first and second directions is commenced from acenterline passing substantially through the substrate feature. Layingdown the composite tape strips may be performed by sequentiallyactivating individual tape threading mechanisms on the fiber placementhead.

According to another disclosed embodiment, a fiber tape placementapparatus is provided for placing fiber tape on a substrate, comprising:a plurality of tape supply devices each holding a supply of fiber tape;a device for compacting the tape on the substrate; a plurality ofthreading mechanisms respectively associated with the tape supplydevices and each operable for initiating tape feed from one of the tapesupply devices to the compaction device; and, a cutting device includinga single cutting blade for cutting the ends of all the tapes fed to thecompaction device substantially simultaneously. The cutting bladeincludes a cutting edge extending transversely across the paths alongwhich the tapes are fed to the compaction device. The cutting device mayinclude an actuator for displacing the cutting blade toward and awayfrom the tapes. The tapes may be arranged in side-by-side relationshipas the tapes are fed to the compaction device, and the cutting blade maybe positioned to cut the ends of the tapes while the tapes are inside-by-side relationship.

The disclosed embodiments satisfy a need for an automatic fiberplacement apparatus having reduced complexity, and a related method thatallows layups to be formed having contoured patterns.

Other features, benefits and advantages of the disclosed embodimentswill become apparent from the following description of embodiments, whenviewed in accordance with the attached drawings and appended claims

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is a perspective view of a single part fabrication cell having areduced complexity fiber placement machine.

FIG. 2 is a perspective view of a large scale fiber placement cellhaving a reduced complexity fiber placement machine.

FIG. 3 is a block diagram illustrating the basic components of thereduced complexity fiber placement machine.

FIG. 4 is a side view of the reduced complexity fiber placement machine.

FIG. 5 is a top view of the machine shown in FIG. 4.

FIG. 6 is a bottom view of the machine shown in FIG. 4.

FIG. 7 is an exploded, perspective view of a rethread assembly formingpart of the machine shown in FIGS. 4-6.

FIG. 8 is a perspective view of the rethread assembly.

FIG. 9 is a perspective view of the machine shown in FIGS. 4-6, a coverhaving been removed to show additional details.

FIG. 10 is a simplified front elevational view of the tape cuttingmechanism forming part of the machine shown in FIGS. 4-9.

FIG. 11 is a perspective view of a tool on which a band of tapes hasbeen placed using the reduced complexity tape placement machine.

FIG. 12 is a plan view of one tape band illustrating the sequential,timed starting points of individual tape strips ending at a commoncutting point.

FIG. 13 is a flow diagram illustrating the basic steps of one method forplacing composite tape on a substrate using the reduced complexityautomatic fiber placement machine.

FIG. 14 is a diagrammatic, plan view showing an alternate method forplacing contiguous strips of tape on a substrate.

FIG. 15 is a flow diagram illustrating in more detail the alternatemethod for placing tape on a substrate shown in FIG. 14.

FIG. 16 is a plan view showing two bands of tape strips placed around asubstrate feature.

FIG. 17 is a flow diagram illustrating a method for placing tape stripsaround the substrate feature shown in FIG. 16.

FIG. 18 is a flow diagram of aircraft production and servicemethodology.

FIG. 19 is a block diagram of an aircraft.

DETAILED DESCRIPTION

Referring first to FIG. 1, a single part fabrication cell generallyindicated by the numeral 18 employs a reduced complexity composite fiberplacement (AFP) machine 20 that may be used to layup relatively small,individual parts 26 over a tool 28. The AFP machine 20 may be partiallyor fully automatically controlled by a suitable controller (not shown)which may comprise a NC, CNC or PLC controller. The AFP machine 20 mayalso be at least partially controlled by an operator 24.

In the illustrated example, the AFP machine 20 is mounted for movementalong orthogonal x,y,z axes shown at 25. More particularly, a tapeapplication head 40 is mounted on a guide 30 for sliding movement alongthe Z axis, and the guide 30, in turn, is mounted on a gantry 32 forsliding movement along the x axis. The gantry 32 is mounted for slidingmovement along the z axis by means of rails 34 that are supported on atable 22. The AFP machine includes tape supply reels 38 which supplycomposite fiber tape 36 to the application head 40 which includes acompaction roller 42 for compacting the tape 36 against the tool 28. Asused herein, “composite fiber tape”, “fiber tape”, “tape” and “tapestrips” are intended to include a wide range of tapes, “tows” androvings, including those having standard widths such as, withoutlimitation, three inches or six inches, and those having nonstandardwidths such as one-eighth inch or one-quarter inch (“tows”).

As will be described later in more detail, the tape 36 is drawn from thereels 38 by a later discussed tape threading mechanism which feeds tapeto a nip (not shown) between the compaction roller 42 and the surface ofthe tool 28. Movement of the AFP machine 20 draws tape 36 from the reels38, and the tape 36 is cut to length by a later discussed, simplifiedtape cutting mechanism.

Referring now to FIG. 2, an alternate form of the AFP machine 20 a maybe used as an end effector installed on a robot 44 which is mounted fortranslation along rails 46. A tool, such as a cylindrical mandrel 50 ismounted by spindles 42 for rotation on supports 54. Rotation of the tool50, as well as the operation of the robot 44 and the placement head 20 amay be controlled by a NC or CNC controller 48. The placement head 20 amay be used to layup bands 28 of the tape 36 on the mandrel 50 with highcontour resolution.

Referring now to FIG. 3, the AFP machine 20 broadly includes asimplified tape supply system 56, tape alignment and independentrethread modules 58, and a single tape cutting mechanism 70 which isused to cut all of the tapes 36. The simplified material supply system56 may comprise a number of individual tape supply modules 57 that arerespectively associated with and draw tape 36 from the pre-wound tapereels 38 (FIG. 1).

Each of the tape supply modules 57 may include a simple tension dragbrake (not shown) and an inertia limiting device such as a pneumaticallyoperated disc brake (not shown), which together act to supply the tape36 to the respectively associated tape alignment and rethread module 58,in a uniform, aligned manner. The tape alignment and rethread modules 58align the plurality of individual tapes 36 in parallel, edge-to-edgecontact using a combination of slotted guides (not shown) which may bepreset in a weave pattern to provide mechanism clearance. Packagedwithin each alignment and rethread module 58 is a tape rethreadmechanism 90 (FIG. 6). Although not specifically shown in the Figures,the tape rethread mechanism 90 uses frictional contact to drive andclamp the individual tapes 36. Additional details of the tape supplymodules 57, the alignment and rethread modules 58 and the rethreadmechanisms 90 may be found in U.S. Pat. No. 4,699,683, issued Oct. 13,1987 and US Patent Publication No. 20070029030A1 published Feb. 8, 2007,the entire contents of both of which are incorporated by referenceherein.

Referring now to FIGS. 4-9, the tape placement head 40 includes a frameassembly 41 having a top plate 62 adapted to be connected to a robot 44(FIG. 2) or other tool used for moving the placement head 40 across asubstrate on which tape 36 is to be placed. The tape alignment andrethread modules 58 are mounted side-by-side on a central body 91 (FIG.7) held within the frame assembly 41. Each of the modules 58 includes amating set of flat rollers 72 and U-shaped rollers 74 that form anentrance channel 76 for one of the tapes 36. The flat rollers 72 aremounted on a shaft 60 that is carried on a pivoting arm 66. Springs 84bias the pivoting arms 66 toward a normal closed position in which theflat rollers are spaced a preselected distance from the U-shaped rollers74, generally corresponding to the thickness of the tape 36. The heightor thickness of the entrance channel. 76 may be adjusted through a setscrew 68. The tapes 36 supplied from reels 38 (FIG. 1) are respectivelyreceived into the entrance channels 76 and are maintained inside-by-side, registered relationship by slotted guides 80 (FIG. 7)which are enclosed by a cover plate 93.

Tapes 36 are fed though the slotted guides 80 to rethread mechanisms 90which include tape engaging rollers 90 a which are moved into engagementwith the tapes 36 by pneumatic cylinders 86. The rollers 90 a are drivenby a belt 97 powered by a motor 99. Actuation of a particular rethreadmechanism 90 initiates threading of the corresponding tape 36 which isthen fed through one of the slotted guides 80 to a guide member 83 whichthen directs the tape 36 at a predetermined angle into the nip 74 wherethe tape 36 is applied and compacted on the substrate 28 by thecompaction roller 42. Fiber optic sensors 89 (FIG. 9) sense the positionof the tapes 36, including passage of the ends of the tapes 36, andproduce position signals that may be used to control tape feed andplacement. The fiber optic sensors 89 also may be used to sense theoperation of the blade 92, either to allow synchronization of itsoperation with other functions in the AFP machine 20, or simply toverify that the blade 92 is operating properly, or both.

From the foregoing, it may be appreciated that the location on thesubstrate surface 82 (FIG. 4) at which a particular tape 36 “starts” isdependent on the point in time when which the tape threading mechanism90 is actuated to begin feeding tape 36 to the compaction roller 42.Since the tape threading mechanisms 90 can be independently actuated byactuators 86, the starting point of each tape 36 can be independentlycontrolled so that these starting points may be staggered in any desiredpattern, as will be described in more detail below.

As best seen in FIG. 9, in accordance with the disclosed embodiment, thetape placement head 40 further includes a tape cutting mechanism 70comprising a pneumatic actuator 96 that reciprocates a single cuttingblade 92. The pneumatic actuator 96 receives air from an air manifoldwhich is controlled by an electric valve control cylinder 87. Thecutting mechanism is also diagrammatically illustrated in FIG. 10. Thesingle cutting blade 92 is connected to the pneumatic actuator 96through a suitable drive linkage 98. The blade 92 includes a cuttingedge 92 a that spans the entire band 106 of tapes laid down by theplacement head 40. Blade 92 reciprocates, as indicated by the arrow 100in FIG. 10, so as to simultaneously sever the entire band 106 of tapes36 in a single shear cut. As will be apparent from the descriptionbelow, the ends of the tapes 36 are cut at the same point during thetape laydown process, regardless of the starting point of the tapes 36.

As used herein, reference to cutting all of the tapes 36 in a band 106“simultaneously” or “substantially simultaneously” means that the blade92 or other cutting device severs all of the tapes 36 in the band 106 atsubstantially the same point at the end of a course. Thus, a cutter (notshown) could be drawn transversely across the band 106 in a singlestroke to sequentially cut the tapes in a band 106 at the end of thecourse, instead of contacting and severing all of the tapes 36 in theband 106 at exactly the same time, as shown in the illustratedembodiment. Further, reference to cutting the tapes 36 in a band 106 ina “single cut” or “single blade stroke” likewise means that all of thetapes 36 in a band 106 are cut at substantially the same point at theend of a course through the motion of a single cutter which contacts andsevers the tapes at this ending point either simultaneously or in rapidsuccession.

Reference is now made to FIGS. 11-13 which illustrate one methodembodiment for forming layups using the reduced complexity AFP machine20. In the example illustrated in FIG. 11, a contoured band 106 ofparallel, contiguous tape strips 36 are laid up on a tool 102 supportedon a base 104. The tool 102 includes a contoured edge 108 to which acontoured portion 88 of the band 106 may substantially conform. As shownat step 114 in FIG. 13, the placement head 40 is first moved to astarting position which corresponds to the starting point “A” of tapenumber 1 in the band 106. As shown at step 116 in FIG. 13, and in FIG.11, the placement head 40 is translated in the direction of travel 112from the starting position “A” to an ending position “G”. At step 118,as the placement head 40 moves from the starting position “A” to theending position “G”, the individual tape threading mechanisms 90 areactuated to start the placement of tapes 1-6 in a sequential manner sothat they are respectively added at points A-F.

The sequential starting of tapes 1-6 described above staggers thebeginnings of tapes 36 so that they form the edge contour or outerprofile 88 (FIG. 11) which generally matches the contoured edge 108 ofthe tool 102. The sequential addition of the tapes 36 to the band 107continues until the band 106 becomes uniform at point “F”. At apreselected point, as shown at step 120, the cutting mechanism 70 isactuated so as to cut the entire band 106 at the ending or cut point“G”, in a single shear cut by the blade 92. It may be appreciated thatthe resolution of the outer profile 88 may be determined by the numberof tapes 36 present under the cutting mechanism 70 at the time thesingle cut is initiated. Hence, for higher resolution areas, a fewernumber of tapes 36 may be included within the width of the band 106 fora particular course.

Attention is now directed to FIGS. 14 and 15 which illustrate analternate method embodiment for placing tape 36 using the reducedcomplexity AFP machine 20. Beginning at step 124, the placement head 40is moved to a starting position 121, in preparation for the placement oftape number 1. As shown in steps 126 and 128, as the placement head 40is translated in the direction of travel 112, a single tape threadingmechanism 90 is activated, thereby causing tape number 1 to be placed onthe tool substrate 82. As shown at step 130, tape number 1 is cut at theend of the course or cut point indicated by the numeral 122.

Next, the placement head 40 is translated through a return path 123 to astarting position for tape number 2, as shown at step 132. At steps 134and 136, the placement head 40 is again translated in the direction ofarrow 112, while one of the tape threading mechanisms 90 is activated tobegin laying tape number 2 parallel with and contiguous to tape number1. Tape number 2 is severed by the cutting mechanism 90 at the cut point122. Next, at step 140, the process of translating the placement head 40through a return path to the next tape starting position 129 is repeatedfor each of the subsequent individual course of tape 36.

In the illustrated example, the tape head 40 is translated from thestarting point 129 to the cut point 122 during which one of the tapethreading mechanisms 90 is activated to lay down tape number 3, which isthen cut by the cutting mechanism 70 at the cut point 122. As previouslynoted, the resolution of the cutting pattern or ramped profile 88 isdetermined by the number of tapes 36 that are present under the cutter70 at the time the tapes 36 are cut. Thus, using the method illustratedin FIGS. 14 and 15, a fewer number of tapes 36 may be included withinthe total course band 106 in order to achieve higher profile resolution.While only a single tape 36 is placed and cut in the illustrated exampleduring each pass of the tape placement head 40, two or more tapes 36 maybe simultaneously placed and cut to produce the desired resolution,depending upon the application.

Attention is now directed to FIGS. 16 and 17 which illustrate a furthermethod embodiment in which the reduced complexity AFP machine 20 is usedto layup tape 36 around a substrate feature, which in the illustratedexample, comprise future througholes to be formed in a substrate 145.Beginning at step 150, the placement head is moved to a startingposition corresponding to the centerline 142 of the substrate features148. Next at 152, the placement head 40 is translated in one directionof travel 112 from the centerline 142 to and ending position 144. Duringtranslation of the placement head 40, the tape threading mechanisms 90are actuated, as shown at 154, thereby laying down a first band of tapes147 wherein the starting points of the individual tapes 36 form a rampedpattern which are stepped around the substrate features 148. All of thetapes 36 in the first band 147 are simultaneously cut at 144, as shownat step 156 in FIGS. 16 and 17.

Next, the placement head 40 is moved back to the centerline position142, as shown at step 158, in preparation for placing a second course149. As shown at step 160, the head 40 is translated from the centerline142 to an ending position 146, during which the tape threadingmechanisms 90 are actuated in a predetermined time sequence so that thestarting positions of the individual tapes 36 in the second band 149form a ramp pattern that is stepped around the substrate features 148.At step 164, all of the tape strips 36 in the second band 149 aresevered simultaneously at the end or cutting point 146.

Embodiments of the disclosure may find use in a variety of potentialapplications, particularly in the transportation industry, including forexample, aerospace, marine and automotive applications. Thus, referringnow to FIGS. 18 and 19, embodiments of the disclosure may be used in thecontext of an aircraft manufacturing and service method 166 as shown inFIG. 18 and an aircraft 167 as shown in FIG. 19. Aircraft applicationsof the disclosed embodiments may include, for example, withoutlimitation, composite stiffened members such as fuselage skins, wingskins, control surfaces, hatches, floor panels, door panels, accesspanels and empennages, to name a few. During pre-production, exemplarymethod 166 may include specification and design 168 of the aircraft 167and material procurement 170. During production, component andsubassembly manufacturing 172 and system integration 174 of the aircraft167 takes place. Thereafter, the aircraft 167 may go throughcertification and delivery 176 in order to be placed in service 178.While in service by a customer, the aircraft 167 is scheduled forroutine maintenance and service 180 (which may also includemodification, reconfiguration, refurbishment, and so on).

Each of the processes of method 90 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 19, the aircraft 167 produced by exemplary method 166may include an airframe 182 with a plurality of systems 184 and aninterior 186. Examples of high-level systems 184 include one or more ofa propulsion system 188, an electrical system 190, a hydraulic system192, and an environmental system 194. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of thedisclosure may be applied to other industries, such as the marine andautomotive industries.

Systems and methods embodied herein may be employed during any one ormore of the stages of the production and service method 166. Forexample, components or subassemblies corresponding to production process166 may be fabricated or manufactured in a manner similar to componentsor subassemblies produced while the aircraft 167 is in service. Also,one or more apparatus embodiments, method embodiments, or a combinationthereof may be utilized during the production stages 172 and 174, forexample, by substantially expediting assembly of or reducing the cost ofan aircraft 167. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while the aircraft167 is in service, for example and without limitation, to maintenanceand service 180.

Although the embodiments of this disclosure have been described withrespect to certain exemplary embodiments, it is to be understood thatthe specific embodiments are for purposes of illustration and notlimitation, as other variations will occur to those of skill in the art.

What is claimed is:
 1. A fiber tape placement apparatus for placingfiber tape on a substrate, the fiber tape placement apparatus consistingof only: a plurality of tape supply devices each holding a supply offiber tape; a device for compacting the fiber tape on the substrate; afirst pivoting arm having a first end located to receive a supply offiber tape and a second end opposite the first end; a second pivotingarm having a third end located to receive the supply of fiber tape and afourth end opposite the third end, wherein the second end of the firstpivoting arm is pivotally connected to the fourth end of the secondpivoting arm; a plurality of threading mechanisms each operable forinitiating tape feed from one of the tape supply devices to the devicefor compacting such that each tape strip individually fed to thesubstrate and placed on the substrate is contiguous with another of thetape strips, wherein the plurality of threading mechanisms comprises: afirst plurality of substantially flat rollers disposed at the first endof the first pivoting arm; a second plurality of substantially flatrollers disposed at the third end of the second pivoting arm; and aplurality of U-shaped rollers, each of the plurality of U-shaped rollersbeing associated with corresponding ones of the first plurality ofsubstantially flat rollers and the second plurality of substantiallyflat rollers, wherein the plurality of U-shaped rollers form nips withthe flat rollers through which the fiber tape is fed; a spring connectedto the first pivoting arm and to the second pivoting arm, the springconfigured to bias the first pivoting arm toward the second pivoting armat the first end and the third end; a first set screw at the first endof the first pivoting arm and a second set screw at the third end of thesecond pivoting arm, wherein the first set screw and the second setscrew are adjustable to adjust a height of entrance channels between theplurality of substantially flat rollers and the plurality of U-shapedrollers; and a cutting device including a single cutting blade forcutting, with a single cut, the ends of all of the tapes fed to thedevice for compacting substantially simultaneously.
 2. The fiber tapeplacement apparatus of claim 1, wherein the cutting blade includes acutting edge extending transversely across the paths along which thetapes are feed to the compaction device.
 3. The fiber tape placementapparatus of claim 1, wherein: the tapes are arranged side-by-side asthe tapes are fed to the compaction device, and the cutting blade isposition to cut the ends of the tapes while the tapes are inside-by-side relationship.
 4. A fiber tape placement head for placingfiber tape on a substrate having a feature, the fiber tape placementhead consisting of only: a plurality of guides for guiding the movementof the fiber tape; a first pivoting arm having a first end located toreceive a supply of fiber tape and a second end opposite the first end;a second pivoting arm having a third end located to receive the supplyof fiber tape and a fourth end opposite the third end, wherein thesecond end of the first pivoting arm is pivotally connected to thefourth end of the second pivoting arm; a plurality of threadingmechanisms for respectively starting tape feed from the tape supplydevices such that each tape strip individually fed to the substrate andplaced on the substrate is contiguous with another of the tape strips,wherein the plurality of threading mechanisms comprises: a firstplurality of substantially flat rollers disposed at the first end of thefirst pivoting arm; a second plurality of substantially flat rollersdisposed at the third end of the second pivoting arm; and a plurality ofU-shaped rollers, each of the plurality of U-shaped rollers beingassociated with corresponding ones of the first plurality ofsubstantially flat rollers and the second plurality of substantiallyflat rollers, wherein the plurality of U-shaped rollers form nips withthe flat rollers through which the fiber tape is fed; a spring connectedto the first pivoting arm and to the second pivoting arm, the springconfigured to bias the first pivoting arm toward the second pivoting armat the first end and the third end; a first set screw at the first endof the first pivoting arm and a second set screw at the third end of thesecond pivoting arm, wherein the first set screw and the second setscrew are adjustable to adjust a height of entrance channels between theplurality of substantially flat rollers and the plurality of U-shapedrollers; a compaction roller for receiving the fiber tape fed by thethreading mechanisms and for compacting the fiber tape on the substrate;and a tape cutting mechanism between the threading mechanisms and thecompaction roller, the cutting mechanism including a single actuator anda single cutting blade for simultaneously cutting the ends of all of thefiber tape in a single stroke.
 5. The apparatus of claim 1, furthercomprising: a plurality of actuators configured to sequentially starttape placement from the plurality of tape supply devices so that atleast one tape strip from the plurality of tape supply devices has astart staggered relative to other tape strips from the plurality of tapesupply devices.